Object Oriented Programming in Swift Ch1 - Inheritance
- 1. Object Oriented Programming in Swift Ch 1: Inheritance Sai Li @ Yowoo Tech. 2016/12/5
- 2. References âą Agile Software Development: Principles, Patterns, and Practice ( : )âš by Robert C. Martin âą Fundamental Object Oriented Programming âš by Hsuan-Tien Lin âą âš by Teddy Chen âą Essential Object-Oriented Programmingâš by Josh Ko
- 3. OOP âą Encapsulation âą Inheritance âą Polymorphism
- 5. Inheritance
- 6. Has-A âą Has-A: a basic way to reuse variables/methods in other classes
- 7. Has-A âą Has-A: a basic way to deïŹne components of a system âą iPhone has a camera
- 8. Has-A âą Has-A: a basic mechanism for objects to connect with each other âą He has 2 friends: Tom and Jerry
- 9. Has-A: most basic design component of OOP
- 10. chi âą Admin is a user âą can be implemented via has-a:âš Everyone has Brokeback Mountain in mind child
- 11. âą Type A inherit TypeB: TypeA is a (special case of) TypeB âą TypeSubClass (TypeDerivedClass or ChildClass) inheritâš TypeSuperClass (TypeBaseClass or ParentClass)
- 12. is-a != has-a
- 13. Uses of Is-A âą CDAndCassetePlayer is a CassettePlayer
- 14. Uses of Is-A âą CassettePlayer is a (concrete type of) Player âą CDPlayer is a (concrete type of) Player
- 15. Uses of Is-A âą CDplayer is a (update of) CassettePlayer âą some behaviors âchangedâ âą no as clear as the previous case, but a potential trick in OOP
- 16. âą Multiple inheritance: Not supported in Swift âą Swift: single inheritance (Java)
- 18. Diamond Problem
- 19. Is-A âą is an extended type ofâš - FunPerson is Person who can tell jokes âą is a more concrete/restricted description of âš - YoungPerson is Person who is young âą (is an update of)âš - NewStaff replaces ExistingStaff
- 21. âą Over-use of inherit for is-a: 1 class -> 1 instance âą Usual goal of OOP: one class, many instances
- 22. Is-A âą Under-user of inherit for is-a: overly complicated class YowooStaff âą Bugs/hacks?âš cali = YowooStaff(id: ââ, name: âCYLiâ, title: âCFOâ)
- 23. Terminology
- 24. Instance Variables and Inheritance âą Staff: 1 instance variables âą YowooStaff: 2 instance variables
- 25. Instance Variables and Inheritance
- 26. âą instance variable binding: determined at compile time âą same ânameâ can NOT co-exist in a class, binding determined by compile-time type.
- 27. Instance Methods and Inheritance âą Staff: 1 instance method âą RD: 2 instance methods
- 28. âą what output?
- 29. âą instance method binding: dynamic, depending on run-time instance types
- 30. Reference Assignment âą saiLi is an instance of GoodStudent âą saiLi is an instance of Student, too âą one instance, many coherent types
- 31. Constructor and Inheritance âą initialize self ïŹrst, ancestor last âą the GoodStudent part of the memory initialized ïŹrst,âš the Student part
- 34. Private Variables and Inheritance
- 35. private variables are still âinheritedâ in memory, but not âvisibleâ to the subclass because of encapsulation (security)
- 36. âą protected: accessible to Child(subclass)
- 37. âą public: everyone âą internal (default): same package classes âą protected: sub-classes âą private: class self Swift Access Permissions
- 38. Access Permission (Swift) âą Child: same or more close than Parent
- 39. References âą Apple: Access Control and protected âą http://commons.oreilly.com/wiki/images/a/a7/ Beyond_Java_I_2_tt13.png âą https://upload.wikimedia.org/wikipedia/commons/ thumb/4/47/C3_linearization_example.svg/600px- C3_linearization_example.svg.png âą https://developer.apple.com/library/content/ documentation/Swift/Conceptual/ Swift_Programming_Language/Art/ initializerDelegation02_2x.png